I’m currently kitbashing a NJ Transit GP40PH-2 locomotive and thankfully it’s still undecorated. I HAD the bosy shell completed 2 - 3 months ago and last night I picked it up and the two halves where I spliced the locomotive together just fell appart.
I used Testors plastic sement and a piece of thin styrene to hold them together. I also used Squadron White Putty to fill the seam. Is there a better glue to use when joining plastic and styrene? Would CA glue work better? The shell has undergone light handling since I completed it. Any ideas? Thank you.
Perhaps you could try the CA, but I wouldn’t put much stock in it for this purpose. I would use Ambroid, maybe, and also those strips to serve as reinforcing blocks as you intended earlier.
If it is an Atlas or Kato shell you need Tenax or “the Same Stuff” from Micromart as the shell is made of ABS plastic, any other shell should be fine with any liquid styrene cement.
For styrene plastic, which is used to mold the shells of everything, locomotives and cars, you want a solvent weld. That’s a very active solvent that actually dissolves the styrene back into goo. Press the goo together, wait for the solvent to evaporate, and you have a joint as strong as the original material. That assumes you have a good fit on the joint. The solvent doesn’t fill gaps. You need to sand the cut edges of your shell until the saw marks are all gone. Glue the sandpaper to something flat, to keep the sanded surface flat and square. Start with something medium like 120 grit, and finish up with something fine, 220 grit or finer. The joint should fit so tightly that you cannot see light thru it.
Ambroid, Testors, Tenax and others sell solvent in little one ounce bottles for about $4. I never noticed much difference between the various brands. They all work the same for me. Right now I am using straight MEK which I get in the Walmart paint dept for $5 a quart. Others have used lacquer thinner. Apply the solvent to the inside of the joint with a brush and let capillary action suck it into the joint.
Another secret of success is to clamp the joint, to hold the surfaces together and keep everything lined up. For a diesel shell, I might cut a piece of wood to fit nicely inside the shell and keep the two edges lined up, and then snap a rubber band about the shell outside to keep it pressed together.
Thanks for all the advice. The shell is a Bachmann shell. Don’t know if that’s a different plastic from Atlas or Kato though. Are there any sort of glues that I’d be able to pickup at Home Depot? If so I could stop on my way home tonight. No Walmarts or Targets anywhere near by. Thanks.
MEK is the active ingredient in many liquid plastic “welding glues” and is available at the local hardware stores in small and large cans for cheap.
A word of caution: this stuff is not great for your health, so be aware of its’ health risks (holds true for other solvent based stuff we all use in making models).
MEK is very hot and you get an immediate bond as soon as it touches mating surfaces, so there is no second chance.
I just happened to do a kitbash of a NJT GP40PH-2B. I started with an Athearn GP38-2, an old Rail Power Products SD45 shell and used the rear steps and front ant-climber from a tunnel motor shell.
If you’re not sure of type of plastic, do a test inside the shell to test the actual bond w/ 'styrene" cement. Testors liquid or MEK can dry quite rapidly and it may be possible that when first splicing the halves, the glue may have started to dry before any “melting” of the true bond of the plastics. If a piece of styrene glued to the inner shell looses bond and can be easily separated/ pried apart, then try the tenax or other sutible for ABS. I perfer Faller Xpert or the testor’s Model master. These allow more time in positioning and slower drying, yet still provides a strong “weld”
The big box stores are not likely to carry the model cements but probably will carry the MEK in the paint department. Hobby Lobby and Michaels should carry the Testors Liquid Cement.
Also, in addition to the butt joint to join the halfs, it would be a good idea to reinforce the joint with some sheet styrene or other similar plastic. That is assuming there is enough room inside for the additional thinckness.
Plastruct Plastic Weld would have been the proper solvent. Be sure to rough up both surfaces especially the splice. A lot of people make that mistake…those solvents work by capillary action so it would have flowed and started to weld faster and stronger, instead of a smooth surface. That’s one reason why it broke apart. The glue only touched the surface, it did not actually weld it together.